/*
 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

#ifndef ZSTD_COMPILER_H
#define ZSTD_COMPILER_H

/*-*******************************************************
 *  Compiler specifics
 *********************************************************/
/* force inlining */

#if !defined(ZSTD_NO_INLINE)
#if defined(__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
#define INLINE_KEYWORD inline
#else
#define INLINE_KEYWORD
#endif

#if defined(__GNUC__)
#define FORCE_INLINE_ATTR __attribute__((always_inline))
#elif defined(_MSC_VER)
#define FORCE_INLINE_ATTR __forceinline
#else
#define FORCE_INLINE_ATTR
#endif

#else

#define INLINE_KEYWORD
#define FORCE_INLINE_ATTR

#endif

/**
 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant
 * parameters. They must be inlined for the compiler to elimininate the constant
 * branches.
 */
#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
/**
 * HINT_INLINE is used to help the compiler generate better code. It is *not*
 * used for "templates", so it can be tweaked based on the compilers
 * performance.
 *
 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the
 * always_inline attribute.
 *
 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline
 * attribute.
 */
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
#define HINT_INLINE static INLINE_KEYWORD
#else
#define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR
#endif

/* force no inlining */
#ifdef _MSC_VER
#define FORCE_NOINLINE static __declspec(noinline)
#else
#ifdef __GNUC__
#define FORCE_NOINLINE static __attribute__((__noinline__))
#else
#define FORCE_NOINLINE static
#endif
#endif

/* target attribute */
#ifndef __has_attribute
#define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
#endif
#if defined(__GNUC__)
#define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
#else
#define TARGET_ATTRIBUTE(target)
#endif

/* Enable runtime BMI2 dispatch based on the CPU.
 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
 */
#ifndef DYNAMIC_BMI2
#if ((defined(__clang__) && __has_attribute(__target__)) ||                               \
     (defined(__GNUC__) && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) && \
    (defined(__x86_64__) || defined(_M_X86)) && !defined(__BMI2__)
#define DYNAMIC_BMI2 1
#else
#define DYNAMIC_BMI2 0
#endif
#endif

/* prefetch
 * can be disabled, by declaring NO_PREFETCH build macro */
#if defined(NO_PREFETCH)
#define PREFETCH_L1(ptr) (void)(ptr) /* disabled */
#define PREFETCH_L2(ptr) (void)(ptr) /* disabled */
#else
#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */
#include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
#define PREFETCH_L1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0)
#define PREFETCH_L2(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
#elif defined(__GNUC__) && ((__GNUC__ >= 4) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)))
#define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)
#define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
#else
#define PREFETCH_L1(ptr) (void)(ptr) /* disabled */
#define PREFETCH_L2(ptr) (void)(ptr) /* disabled */
#endif
#endif /* NO_PREFETCH */

#define CACHELINE_SIZE 64

#define PREFETCH_AREA(p, s)                                \
  {                                                        \
    const char* const _ptr = (const char*)(p);             \
    size_t const _size = (size_t)(s);                      \
    size_t _pos;                                           \
    for (_pos = 0; _pos < _size; _pos += CACHELINE_SIZE) { \
      PREFETCH_L2(_ptr + _pos);                            \
    }                                                      \
  }

/* disable warnings */
#ifdef _MSC_VER                 /* Visual Studio */
#include <intrin.h>             /* For Visual 2005 */
#pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */
#pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
#pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
#pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */
#pragma warning(disable : 4324) /* disable: C4324: padded structure */
#endif

#endif /* ZSTD_COMPILER_H */
